package view;

import java.nio.ByteBuffer;
import java.nio.ByteOrder;
import java.nio.FloatBuffer;
import java.nio.ShortBuffer;
import java.util.Arrays;

import model.Dimension;
import model.OnScreen;
import model.Snippet;
import model.location.ScreenArea;
import android.opengl.GLES20;
import android.util.Log;


public class Square 
{	
	private static final String TAG = "SQUARE";	
	
	private static final String vertexShaderCode =
            // This matrix member variable provides a hook to manipulate
            // the coordinates of the objects that use this vertex shader
            "uniform mat4 uMVPMatrix;" +
            "attribute vec4 vPosition;" +
            "void main() {" +
            // The matrix must be included as a modifier of gl_Position.
            // Note that the uMVPMatrix factor *must be first* in order
            // for the matrix multiplication product to be correct.
            "  gl_Position = uMVPMatrix * vPosition;" +
            "}";

	private static final String fragmentShaderCode =
            "precision mediump float;" +
            "uniform vec4 vColor;" +
            "void main() {" +
            "  gl_FragColor = vColor;" +
            "}";
//
//    private static final int vertexShader = SnippetRenderer.loadShader(
//            GLES20.GL_VERTEX_SHADER, vertexShaderCode);
//	private static final int fragmentShader = SnippetRenderer.loadShader(
//            GLES20.GL_FRAGMENT_SHADER, fragmentShaderCode);
	
    
    private FloatBuffer vertexBuffer;
    private final ShortBuffer drawListBuffer;
    private final int mProgram;
    private int mPositionHandle;
    private int mColorHandle;
    private int mMVPMatrixHandle;

    // number of coordinates per vertex in this array
    static final int COORDS_PER_VERTEX = 3;

    static float squareCoords[] = {
            -0.5f,  0.5f, 0.0f,   // top left
            -0.5f, -0.5f, 0.0f,   // bottom left
             0.5f, -0.5f, 0.0f,   // bottom right
             0.5f,  0.5f, 0.0f }; // top right

    private final short drawOrder[] = { 0, 1, 2, 0, 2, 3 }; // order to draw vertices

    private final int vertexStride = COORDS_PER_VERTEX * 4; // 4 bytes per vertex

    float color[] = { 0.2f, 0.709803922f, 0.898039216f, 1.0f };

    public Square(Snippet snippet)
    {
    	Log.i(TAG, "square creation");
    	ScreenArea screenArea = snippet.getScreenArea();
    	
    	screenAreaToCoords(screenArea);
    	
    	setColor(snippet.isInformation());
    	

        // initialize byte buffer for the draw list
        ByteBuffer dlb = ByteBuffer.allocateDirect(
                // (# of coordinate values * 2 bytes per short)
                drawOrder.length * 2);
        dlb.order(ByteOrder.nativeOrder());
        drawListBuffer = dlb.asShortBuffer();
        drawListBuffer.put(drawOrder);
        drawListBuffer.position(0);

        // prepare shaders and OpenGL program
        int vertexShader = SnippetRenderer.loadShader(
                GLES20.GL_VERTEX_SHADER,
                vertexShaderCode);
        int fragmentShader = SnippetRenderer.loadShader(
                GLES20.GL_FRAGMENT_SHADER,
                fragmentShaderCode);

        Log.e(TAG, String.format("shaders initialized: %d, %d", vertexShader, fragmentShader));
        
        mProgram = GLES20.glCreateProgram();             // create empty OpenGL Program
        GLES20.glAttachShader(mProgram, vertexShader);   // add the vertex shader to program
        GLES20.glAttachShader(mProgram, fragmentShader); // add the fragment shader to program
        GLES20.glLinkProgram(mProgram);                  // create OpenGL program executables
    }
        public void setColor(boolean isGreen) 
    {
    	if(!isGreen)
    		color = new float[] { 1, 0, 0, 0.5f };
    	else 
    		color = new float[] { 0, 1, 0, 0.5f };	
	}
    
    private void coordsToBuffer(float[] coords)
    {
    	// initialize vertex byte buffer for shape coordinates
        ByteBuffer bb = ByteBuffer.allocateDirect(
                // (number of coordinate values * 4 bytes per float)
        		coords.length * 4);
        // use the device hardware's native byte order
        bb.order(ByteOrder.nativeOrder());

        // create a floating point buffer from the ByteBuffer
        vertexBuffer = bb.asFloatBuffer();
        // add the coordinates to the FloatBuffer
        
        vertexBuffer.put(coords);
        // set the buffer to read the first coordinate
        vertexBuffer.position(0);
    }

    public float[] screenAreaToCoords(ScreenArea area)
    {
    	if(area == null)
    		return new float[12];
    	
    	float ratio = OnScreen.getInstance().getLeftTorightCodeScale();
    	   	
    	float[] points = area.getPoints();
    	
    	float height = points[5] - points[1];    	
    	
    	float left = 0, right = 0;
    	
    	if(ratio >= 1)
    		right = ((height * ratio) - height) * 0.5f;
    	else
    		left = ((height * (1/ratio)) - height) * 0.5f;
    	
    	float[] coords = new float[] {
    			getNormValue(points[0], true), getNormValue(points[1] + left, false), 0,
    			getNormValue(points[4], true), getNormValue(points[5] - left, false), 0,
    			getNormValue(points[6], true), getNormValue(points[7] - right, false), 0,
    			getNormValue(points[2], true), getNormValue(points[3] + right, false), 0,    			
    	};
    	
		coordsToBuffer(coords);
    	
    	return coords;
    }
    
    private float getNormValue(float value, boolean isX)
    {
    	Dimension dim = OnScreen.getInstance().getScreenDimension();
    	
    	float width = dim.getWidth();
    	float height = dim.getHeight();
    	
    	if(isX)
    		return (1 - (value / (width * 0.5f))) * -1f;
    	else
    		return 1 - (value / (height * 0.5f));
    }

    /**
     * Encapsulates the OpenGL ES instructions for drawing this shape.
     *
     * @param mvpMatrix - The Model View Project matrix in which to draw
     * this shape.
     */
    public void draw(float[] mvpMatrix) 
    {    	    	
        // Add program to OpenGL environment
        GLES20.glUseProgram(mProgram);

        // get handle to vertex shader's vPosition member
        mPositionHandle = GLES20.glGetAttribLocation(mProgram, "vPosition");

        // Enable a handle to the triangle vertices
        GLES20.glEnableVertexAttribArray(mPositionHandle);

        // Prepare the triangle coordinate data
        GLES20.glVertexAttribPointer(
                mPositionHandle, COORDS_PER_VERTEX,
                GLES20.GL_FLOAT, false,
                vertexStride, vertexBuffer);
        
        // get handle to fragment shader's vColor member
        mColorHandle = GLES20.glGetUniformLocation(mProgram, "vColor");

        // Set color for drawing the triangle
        GLES20.glUniform4fv(mColorHandle, 1, color, 0);

        // get handle to shape's transformation matrix
        mMVPMatrixHandle = GLES20.glGetUniformLocation(mProgram, "uMVPMatrix");
        SnippetRenderer.checkGlError("glGetUniformLocation");

        // Apply the projection and view transformation
        GLES20.glUniformMatrix4fv(mMVPMatrixHandle, 1, false, mvpMatrix, 0);
        SnippetRenderer.checkGlError("glUniformMatrix4fv");

        // Draw the square
        GLES20.glDrawElements(
                GLES20.GL_TRIANGLES, drawOrder.length,
                GLES20.GL_UNSIGNED_SHORT, drawListBuffer);

        // Disable vertex array
        GLES20.glDisableVertexAttribArray(mPositionHandle);
    }

	public void moveToFromCenter(float x, float y) 
	{
		// initialize vertex byte buffer for shape coordinates
        ByteBuffer bb = ByteBuffer.allocateDirect(
                // (number of coordinate values * 4 bytes per float)
        		squareCoords.length * 4);
        // use the device hardware's native byte order
        bb.order(ByteOrder.nativeOrder());

        // create a floating point buffer from the ByteBuffer
        vertexBuffer = bb.asFloatBuffer();
        // add the coordinates to the FloatBuffer
		
		//TL
		squareCoords[0] = x - 0.5f; 
		squareCoords[1] = y + 0.5f;
		//BL
		squareCoords[3] = x - 0.5f;
		squareCoords[4] = y - 0.5f; 
		//BR
		squareCoords[6] = x + 0.5f;
		squareCoords[7] = y - 0.5f;
		//TR
		squareCoords[9] = x + 0.5f;
		squareCoords[10] = y + 0.5f;
		
		vertexBuffer.put(squareCoords);
        // set the buffer to read the first coordinate
        vertexBuffer.position(0);
	}
}